# # def add(a,b):
# #     """加减法"""
# #     return  f'{a+b}'
# #
# #
# # print(add(1,2))
# #
# # help(add)
# #
# # help(type)
# #
# #
# #
# # # 函数说明文档高级使用
# #
# # def sum_test1(a,b):
# #     """
# #     文档设计
# #     :param a:
# #     :param b:
# #     :return:
# #     """
# #     print("aaa")
# #
# #
# # help(sum_test1)
#
# def sum_test(aa):
#     """
#     求和
#     :param aa: 集合
#     :return: 集合中的和
#     """
#     count = 0
#     for a in aa:
#         count += a
#     return count
#
# def sum_dive(aa):
#    count = sum_test(aa)
#    return count / len(aa)
#
#
# aa = [1,2,3,4,3,2]
# print(sum_dive(aa))
# print(15 / 6)


dd = 0
print(dd)

def aa():
    global dd
    dd = 20
print(dd)

def bb():
    dd = 30
aa()

print(dd)
